Insect Order Trichoptera (Caddisflies)
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Kingdom Animalia (Animals)
» Phylum Arthropoda (Arthropods)
» Class Insecta (Insects)
» Order Trichoptera (Caddisflies)
5 families aren't included.
Common Name
| Match | Common Name |
 | Caddisflies |
Fly Imitations by Orvis
| Stage | Fly Pattern |
| Larva | Case Caddis |
| Larva | Czech Mate |
| Emerger | SparkleWing Caddis Emerger |
| Pupa | LaFontaine Sparkle Pupa |
| Adult | Elk Wing Caddis |
Caddis species actually provide as much incentive to learn their specifics as the mayflies do. There is just as much variety in their emergence and egg-laying behaviors, and as many patterns and techniques are needed to match them. Anglers are hampered only by the relative lack of information about caddisfly behavior and identification.
Hatching Behavior
In many species, the pupae become very active just before emergence and drift along the bottom of the river, sometimes for hours. The "deep sparkle pupa" patterns introduced by Gary LaFontaine in Caddisflies are the most popular of many imitations inspired by this behavior. It is a deep nymph fisherman's dream. Sometimes they drift similarly just below the surface for a long time before trying to break through.Pupae of different species use three different methods to emerge:
- Most species rise to the surface and struggle through. They usually take flight quickly once they're out of the water, but slow species first struggle and drift long distances half-submerged as they wriggle free from their pupal shucks (Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.).
Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies. - The pupae of some species crawl out of the water on rocks, sticks, and such, so that the adults emerge high and dry.
- Some pupae rise to the surface and swim quickly across it to shore where they crawl out to emerge.
View Full SizeMost caddis pupae are good swimmers, and they use their legs as paddles rather than wiggling their bodies to move.
After emerging, caddisfly adults live for a long time compared to mayflies, in part because they are able to drink to avoid dehydration (mayfly adults cannot eat or drink). This flight period (Flight period: The span of time that the adults of an adult aquatic insect species are active and flying around, in between emergence and death. It may refer to the average adult lifespan of the individuals of that species, or to the total length of time for which at least some of them are active.) lasts anywhere from a few days to a few months, depending on the species, so mating adults may be seen on or over the water long after emergence is complete.
Egg-Laying Behavior
Many caddisfly females dive underwater to lay their eggs on the stream bottom. Some crawl down objects to do this but most swim right down through the water column. The latter are responsible for my fastest trout fishing action ever -- days when trout raced each other to attack my flies the moment they hit the water, cast after cast.Others lay their eggs on the surface in various ways. They may fly low over the water, periodically dipping their abdomens to lay eggs. Others land on the surface repeatedly, fussing and fluttering in enticing commotion. Less active species may fall spent (Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself.) to the surface with all four wings spread out. Others ride the water serenely while laying their eggs, and they are the easiest to match with the dead-drift (Dead-drift: The manner in which a fly drifts on the water when not moving by itself or by the influence of a line. Trout often prefer dead-drifting prey and imitating the dead-drift in tricky currents is a major challenge of fly fishing.) techniques of mayfly fishermen.
Some egg-laying methods keep the adult females safe from trout altogether. They may drop their eggs into the water from overhanging plants, or lay their eggs on the vegetation itself. That way the eggs don't enter the river until the next rain--an excellent drought survival strategy.
Larva & Pupa Biology
Most caddisfly larvae live in cases they build out of sand, rock, twigs, leaf pieces, and any other kind of underwater debris. Some even generate their own cases out of silk. There is tremendous variation in case style and also in the way the larvae manage their cases: whether they replace it as they grow or renovate their old one, and whether they carry it around or fix it to an object. Trout love to eat these larvae, case and all.Other common caddis larvae build nets instead of cases. These are not residences but hunting traps, like tiny spider webs, designed to capture plankton and smaller aquatic insects the larvae eat. One larva may build more than one net and roam freely around the rocks and logs tending to each and ingesting the catch. The net-spinning families, in order of abundance, are Hydropsychidae, Philopotamidae, and Arctopsychidae.
One large and primitive family of caddisflies, Rhyacophilidae, needs neither cases nor nets. Most of its species are predators who stalk through rocky riffles killing other insect larvae and nymphs.
All of these types are especially prone to behavioral drift (Behavioral drift: The nymphs and larvae of many aquatic insects sometimes release their grip on the bottom and drift downstream for a while with synchronized timing. This phenomenon increases their vulnerability to trout just like emergence, but it is invisible to the angler above the surface. In many species it occurs daily, most often just after dusk or just before dawn.), making them an important food source year-round for the trout in most rivers.
When caddis larvae are full-grown, they seek hiding places to pupate, either in their cases or in special cocoons. They are considered to be pupae throughout the radical reformation from grub-like larva into intricate winged adult. Some of the larva's body mass is consumed as energy for the development of the pupa, so the pupae and adults both have bodies one to three hook sizes smaller than their mature larvae. When pupation is complete, the insect which begins the emergence sequence is called a pharate adult (Pharate adult: Caddisflies are considered to be pupae during their transformation from larva into adult. This transformation is complete before they're ready to emerge. The emerging insect we imitate with the "pupa" patterns we tie is technically called a pharate adult. It is a fully-formed adult caddisfly with one extra layer of exoskeleton surrounding it and restricting its wings.). It is no longer technically a pupa in the language of entomologists, but because anglers universally recognize the term "pupa" I use that convenional misnomer throughout this site.
Sometimes individuals within the same fall-emerging species mature at different rates. In some species, mature larvae compensate for this by entering an inactive phase called diapause (Diapause: A state of complete dormancy deeper even than hibernation. While in diapause, an organism does not move around, eat, or even grow. Some caddisfly larvae enter diapause for a few weeks to several months. Some species of microscopic zooplankton can enter diapause for several hundred years.) prior to pupation. Cool fall weather triggers the end of this phase for every individual within a few short weeks, synchronizing emergences that would otherwise be spread over several months. This boosts the quality of autumn caddisfly hatches like the giant western genus Dicosmoecus.
Trichoptera Fly Fishing Tips
The presence of caddisfly adults in the air does not mean that the angler should immediately switch to an imitation. As Swisher and Richards put it in Selective Trout:They are often seen over the water when they are doing nothing more than flying around.
More often it's the caddisflies you don't see that are important, the females diving underwater to lay their eggs or the pupae drifting below the surface preparing to emerge.
66 Caddisfly Specimens:
Rhyacophila (Green Sedges) Caddisfly Pupa
View 11 PicturesI collected this pupa and several like it from the same stream and on the same day as this larva. I suspect they're the same species. Every pupa I collected was in a brown casing like the one shown in one of the pictures below. I cut this pupa out of its case after a picture so you can see more details. It is close to but not fully developed.
View 11 PicturesI collected this pupa and several like it from the same stream and on the same day as this larva. I suspect they're the same species. Every pupa I collected was in a brown casing like the one shown in one of the pictures below. I cut this pupa out of its case after a picture so you can see more details. It is close to but not fully developed.Region: Upper Midwest
Collected Jun 5, 2005
Added May 25, 2006
Neophylax (Autumn Mottled Sedges) Caddisfly Adult
View 20 PicturesThis large caddisfly looks really neat close-up.
View 20 PicturesThis large caddisfly looks really neat close-up.Region: Northeast
Collected Sep 19, 2006
Added Oct 4, 2006
Rhyacophila fuscula (Green Sedge) Caddisfly Larva
View 11 Pictures
View 11 PicturesRegion: Northeast
Collected Apr 1, 2007
Added Apr 3, 2007
9 Streamside Pictures of Caddisflies:
View Full Size
These caddisflies were thick over the water in the evening on a cold, clear northwoods lake. They were in many places on the lake, all closer to the shady shore, which also was the shore most sheltered from the wind. I'm not sure which of those features attracted them.
In this picture: Caddisfly Genus Nectopsyche (White Millers).
In this picture: Caddisfly Genus Nectopsyche (White Millers).
54 Underwater Pictures of Caddisflies:
Hundreds of cased caddisfly larvae live on this log in a small brook trout stream.
In this picture: Insect Order Trichoptera (Caddisflies).
In this picture: Insect Order Trichoptera (Caddisflies).
There's a large Ephemerella subvaria nymph in the top left.
In this picture: Insect Order Trichoptera (Caddisflies), Mayfly Species Ephemerella invaria (Sulphur), and Mayfly Species Ephemerella subvaria (Hendrickson).
In this picture: Insect Order Trichoptera (Caddisflies), Mayfly Species Ephemerella invaria (Sulphur), and Mayfly Species Ephemerella subvaria (Hendrickson).
Hundreds of cased caddis larvae cling to sparse weed growth in the sand under heavy current.
In this picture: Insect Order Trichoptera (Caddisflies).
In this picture: Insect Order Trichoptera (Caddisflies).
Recent Discussions of Trichoptera
Caddisfly adult ID 3 Replies »
I have a basic understanding of caddis fly IDing when it comes to the larva, but how do you tell the adults apart. You can never have enough useless bug knowledge. :)
Replycaddis fly phonics guide 6 Replies »Posted by SlapNuts on Oct 30, 2009 in the family Brachycentridae
Last reply on Oct 31, 2009 by Taxon
I have trouble pronouncing the scientific names of most caddis flies. Does anyone know where I can find a phonics name list or guide.
Example Ephemerella ef uh mare el uh
Replyplz remove duplicated post refresh makes it send again sorry :(Example Ephemerella ef uh mare el uh
Posted by Deke on Aug 20, 2009
plz remove duplicated post refresh makes it send again sorry :(
Replyfound these in runoff to our creekPosted by Deke on Aug 20, 2009
i was fossil hunting and came across these i live in west tn,i tohught it was a fossil at first then relized its really small pebbles and relized it was some sort of a cacoon ,wondering what can build this i put them in my aquarium for the night as they are crawling ill put them back tommorow.very interesting creatures i have never seen anyhting like this in my creek all my life thought i was on a endagered species hehe.and im pretty sure this is what they are now that i found your site but what is odd is there is no trout in my creek its on the small size and they was only 3 under this rock each about a inch long. they are not to my knowledge at all in the main creek with crawfish's and minnow's i dont have no plankton for them to eat i threw grass in there and spring water it probably has some and a piece of a sardine know that i know they can fly i do not wish to keep them also hehe but they are cute"in a manly way"
Replyfound these in runoff to our creekPosted by Deke on Aug 20, 2009
i was fossil hunting and came across these i live in west tn,i tohught it was a fossil at first then relized its really small pebbles and relized it was some sort of a cacoon ,wondering what can build this i put them in my aquarium for the night as they are crawling ill put them back tommorow.very interesting creatures i have never seen anyhting like this in my creek all my life thought i was on a endagered species hehe.and im pretty sure this is what they are now that i found your site but what is odd is there is no trout in my creek its on the small size and they was only 3 under this rock each about a inch long. they are not to my knowledge at all in the main creek with crawfish's and minnow's i dont have no plankton for them to eat i threw grass in there and spring water it probably has some and a piece of a sardine know that i know they can fly i do not wish to keep them also hehe but they are cute"in a manly way"
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